ETYMOLOGY
from Latin epistola (epistle) + -ist
EXAMPLE
Mrs. Carter to Miss Talbot, Deal, April 16, 1743.
“… I am extremely obliged to you, my dear Miss Talbot, for your account of the Italian epistolists. I find I am not likely to be much edified by their sense, but they may perhaps be of use to me in gaining the improvement I wish for in the language. …”
From: A Series of Letters Between Mrs. Elizabeth Carter and Miss Catherine Talbot, from the year 1741 to 1770
By Elizabeth Carter, 1743
Lexicophilia 